Fuel pump



V. D. ROOs Oct. 9, 1962 FUEL PUMP 5 Sheets-Sheet 1 Filed Feb. 29, 1960 FIG.

FIG. 2

INVENTOR VERNON 0. 9005 ATTORNEY5 Oct. 9, 1962 v. D. ROOSA 3,057,299

FUEL PUMP Filed Feb. 29, 1960 I s Sheets-Sheet 2 INVENTOR v VERNON D. ROOSA W M W ATTORNEYS V. D. ROOSA Oct. 9, 1962 FUEL PUMP 3 Sheets-Sheet {5 Filed Feb. 29, 1960 INVENTOR VERNON D. POOSA ATTORNEYS ite States amazes Patented Oct. 9, 1962 This invention relates to fuel injection systems for internal combustion engines and is concerned, more particularly, with an improved fuel injection pump of the distributor type which has an increased number of injections of fuel in relationship to its driven speed and thus has particular utility for use with two-cycle engines.

As is well known, the operation of a two-cycle internal combustion engine requires the injection of fuel sequentially to all of the cylinders of the engine during a single revolution of the engine crank shaft as compared with the operation of a four-cycle engine where injection of the fuel to all of the cylinders in sequence takes place over a period of two revolutions of the crank shaft. In order to provide the higher frequency fuel injections required for two-cycle engines, it has been the usual practice to drivingly connect the engine to the fuel pump so that the fuel pump shaft will rotate at the same shaft speed as the engine instead of at half speed as is the case when a four-cycle engine is being operated. However, it has been found that fuel injection pumps which will operate effectively and efliciently when used with four-cycle engines will frequently be unsatisfactory from the standpoint of accurate metering and effective pumping action, not to mention wear and maintenance, when operated at the doubled speed of rotation required when the pump is used with a two-cycle engine.

Accordingly, it is an object of the invention to provide a fuel injection pump of the distributor type which will permit fuel injection to the cylinders of an engine at the desired rate and in the desired sequence without requiring excessive driving speeds particularly when used with two-cycle engines. Included in this aim is the provision of a fuel pump which will be extremely durable and reliable in operation, and capable of long use with minimum maintenance. i

A further object of the invention is to provide such a pump which is economical to fabricate and assemble and which is simple and convenient to install particularly from the standpoint of providing connections between the fuel pump and the engine.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a rear elevation view showingan embodiment of the fuel pump of this invention mounted on an engine shown fragrnentarily in phantom;

FIG. 2 is a side elevation view of the pump of FIG. 1, partially in cross section to show the fuel distribution structure;

FIG. 3 is a cross section view taken along the lines 3-3 of FIG. 2;

FIG. 4 is a cross section view taken along the lines 4-4 of FIG. 2;

FIG. 5 is a cross section view similar to the view shown in FIG. 4 of a modified embodiment of my invention;

FIG. 6 is a cross section view similar to FIG. 3 of the modified embodiment of my invention shown in FIG. 5;

and

FIG. 7 is a cross section view similar to FIG. 6 of a further modification of the pump.

For purposes of showing and describing a specific embodiment of the pump of the present invention, there is illustrated in FIGS. 14 of the drawings, by way of example, a specific embodiment of the pump which is designed for use with a four-cylinder engine and which when connected to a four-cylinder, two-cycle engine is intended to be driven at only half the shaft speed of the engine. It will be apparent from the following description, however, that the specific embodiment is only illustrative and that the pump may be readily modified within the teaching of the invention for use with engines having a greater or lesser number of cylinders and for operation at different shaft speed ratios.

Referring to FIGS. 14 in detail, the fuel pump 10 is mounted on the internal combustion engine shown diagrammatically in phantom at 12 by means of bolts 14 passing through flange 16 on the pump housing 18. The housing 18 is connected at its righthand end as viewed in FIG. 2 to the main body member on hydraulic head 20 of the pump. The head 20 has an axial cavity 22 fitted with a stationary liner or sleeve 24. Rotatably mounted in the sleeve 24 is the rotor 26 which is driven in timed relationship by the engine 12 by means of driving connections not shown extending through the flanged end of the housing 18.

At the righthand end of the head 20 as viewed in FIG. 2 there is mounted a pick-up pump 28 having a rotary pumping member, not shown, which is drivingly connected to the rotor 26 for rotation therewith. The pickup pump 28 has an inlet coupling 30 for connection to a fuel tank or reservoir and has its outlet connected to the longitudinal passageway 32 in the head 20. The longitudinal passageway 32 terminates at the circumferential groove 34 which at the diametrically opposite side of the head communicates with a port 36 extending into the radial passageway 38 containing the metering valve 40 by means of which the output of the pump is controlled, the valve 40 being operatively connected to the throttle lever 42.

The radial passageway 38 is intended to feed fuel to the intake passages of the rotor 26. In the specific embodiment shown, the radial passageway 38 communicates at its inner end with a circumferential groove 44 extending about the sleeve 24 which in turn communicates with a plurality of inlet ports 46 spaced at regular intervals around the periphery of the sleeve 24. In the specific embodiment, there are eight such inlet ports 46 spaced equally about the rotor 26 as best shown in FIG. 4 of the drawings.

The rotor 26 has two diametrically arranged orifice slots 48 in its outer periphery which are connected by diagonal passageways 50 with the pump chamber 52. The pump chamber 52 is a transverse cylindrical bore in which are slidably mounted the opposed pistons or plungers 54.

The outer ends of the plungers 54 are adapted to be engaged by a normally stationary peripheral cam 56 having lobes for periodically forcing the plungers inwardly as the rotor is rotated to provide a pumping action in timed relationship to the rotation of the rotor. This portion of the fuel pump is generally similar to that shown in my prior Patent No. 2,641,238 granted June 9, 1953.

Turning now to the fuel distributing portion of the pump, it will be noted that the sleeve 24 is provided with outlet ports 58 which are spaced longitudinally from the inlet ports 46 and which are adapted to communicate sequentially with the slots 48 as the rotor is rotated. There are four of these outlet ports 58 (equal to the number of engine cylinders) and as best shown in FIG. 3, the outlet ports 58 are located only 45 apart, i.e., divided by the number of outlet ports so that all of the outlet ports are located within one half of the periphery of the sleeve 24 and no two ports are in alignment. The outlet ports 58 are in staggered angular relationship with respect to the inlet ports 46, each being intermediate a successive pair of inlet ports when the sleeve 24 is viewed in transverse cross section. The outlet ports 58 communicate with passageways 60 extending through the head 20 which are fitted with couplings 62 for attachment of the usual fuel injection lines (not shown).

The operation of the pump will be apparent from the foregoing description in connection with the following explanation. As the rotor is being rotated, it will be assumed that the slots 48 have been brought into registry with a diametrically opposed pair of inlet ports 46' and thus out of registry with the outlet ports 58. Such a position is shown in FIGS. 2-4 of the drawings. In this position fuel is admitted to the pump chamber 52 from the pick-up pump 28 via valve 40 and the cam 56 is configured to permit the plungers 54 to move apart to receive the metered fuel charge. As rotation continues, the slots 48 move out of registry with the inlet ports 46 to close the same and then one of the slots 48 moves into registry with one of the outlet ports 58. At the same time, the configuration of the cam 56 causes the plungers 54 to be moved together thus injecting a charge of fuel under high pressure to the particular outlet port 58 in registry with said one of the slots. This sequence continues until the one slot has moved beyond the last of the outlet ports 58 whereupon the second slot will come into registry with the first outlet port to repeat the cycle. In brief, the two rotor slots 48 do not function simultaneously but operate in sequence, each distributing a fuel charge to each of the outlet ports in turn during a half rotation of the rotor. As a consequence, each of the outlet ports 58 will receive two separate charges of fuel in timed relationship to a single rotation of the rotor with the result that if the pump is connected to a two-cycle engine it has to be rotated at only half the engine shaft speed and if connected to a four-cycle engine at only one fourth of the engine shaft speed.

In addiiton to the advantages gained as a result of the reduction in rotor speed such as better wear and more accurate and eflicient pumping action, there is a further important advantage in that the location of the couplings 62 throughout only half the periphery of the pump permits the pump to be located in places where the usual circumferentially arranged connections would be inaccessible or difficult to reach during installation or repair. This is illustrated in FIG. 1 of the drawings where all of the couplings 62 are located on the upper portion of the pump where they are readily accessible for connection to the usual injection lines.

In FIGS. 57 of the drawings the arrangement of the inlet and outlet ports for a pump designed for a threecylinder engine has been illustrated particularly to demonstrate an alternate arrangement of the outlet ports throughout the entire periphery of the pump which is possible when the engine has an odd number of cylinders as compared with engines having an even number of cylinders as in the case of the four-cylinder engine previously referred to.

Referring to FIG. 5, the sleeve 124 mounted in the head 120 in this embodiment is provided with only six inlet ports 146 spaced equally about the circumference thereof for the reason that when the pump is used with a three-cylinder engine only six fuel charges are required for each rotation of the rotor. In FIG. 7 of the drawings, the outlet ports 158 are shown arranged in a manner similar to that described in connection with the embodiment shown in FIGS. 1-4 which is to say that the ports 153 are disposed within a 180 span of the sleeve and are located angularly between successive pairs of inlet ports 146. With the ports so arranged, the pump operates in the same manner as previously described except that six metered and timed fuel charges are delivered for each rotation of the pump shaft instead of eight fuel charges.

In the modification shown in FIG. 6 of the drawings, the three outlet ports 258 are arranged symmetrically about the entire periphery of the sleeve 224 and are angularly spaced intermediate alternate pairs of the inlet ports 146 instead of between successive pairs of inlet ports as previously described. This is permitted by the fact that since there are an odd number of outlet ports 258, these may be symmetrically arranged throughout the entire periphery of the pump without bringing any two of the ports into radial alignment. In this modification, the rotor slots 248 in the rotor function alternately during successive injections of fuel which is to say that after one of the slots 248 has moved into and out of registry with one of the outlet ports 258, the second slot 248 moves into and out of registry with the second outlet port 258, whereupon the first slot 248 moves into registry with the third outlet port 258 and so on, thus delivering two separate fuel charges to each of the outlets in timed relationship during a single turn of the rotor 126. It will be noted that in all of the embodiments of the invention, the rotor distributor portion is provided with more than one outlet orifice, which orifices are equally spaced about the periphery of the rotor, and the outlet ports are arranged in the head in angularly related positions such that no more than one outlet port can register with an orifice at a time, yet each of the ports will register with each of the outlet orifices in sequence and in proper timed relationship during a single turn of the rotor.

It thus will be apparent that there has been provided in accordance with the invention, a fuel pump having a materially increased frequency of fuel injections in relationship to its driven speed permitting the pump to be driven at lower efficient speeds even when used with twocycle engines, thus providing increased service life and accuracy with reduction in wear and maintenance.

Variations and modifications of the structures herein described which are apparent within the skill of the art are intended to be included within the scope of the invention.

I claim:

1. In a fuel injection pump for a multiple cylinder internal combustion engine, a pump body, a rotor mounted for rotation in said body containing pumping means, means for connecting the rotor to an engine for rotation thereby, said pump body having a plurality of fuel outlet ports for connection individually to the respective fuel injection lines of an engine with the outlets disposed at the periphery of the rotor in a first common transverse plane, said pump body having a plurality of fuel inlet ports disposed at the periphery of the rotor in a second common transverse plane spaced from the first common transverse plane and being arranged in an equally spaced apart succession, said fuel outlet ports being circumferentially interposed between pairs of at least some of said fuel inlet ports, said rotor having means providing a fuel inlet for registry alternately with said fuel inlet ports and a fuel outlet axially spaced from the fuel inlet to move into registry with successive fuel outlet ports after the fuel inlet has moved out of registry with a fuel inlet port, and cam means actuating the pumping means and contoured to provide a number of pump actuating sections which are a multiple of the number of fuel outlet ports whereby fuel is pumped to each fuel outlet port a plurality of times during each revolution of the rotor.

2. A fuel injection pump as claimed in claim 1 wherein the rotor is provided with a longitudinally disposed fuel groove adapted to move into registry alternately with said fuel inlet ports and with said fuel outlet ports.

3. A fuel injection pump as claimed in claim 1 wherein said rotor is provided with means providing a plurality of diametrically disposed fuel outlets for registry alternately with said fuel outlet ports.

4. A fuel injection pump as claimed in claim 2 Wherein the rotor is provided with a plurality of longitudinally disposed fuel grooves circumferentially spaced and wherein the length of each groove is at least equal to the spacing between the transverse plane of the fuel inlet ports and the transverse plane of the fuel outlet ports.

5. A fuel injection pump as claimed in claim 3 wherein there are twice as many inlet ports as outlet ports, and wherein the inlet ports are angularly related to the outlet ports.

6. A fuel injection pump as claimed in claim 3 Wherein said cam means actuating the pumping means is contoured to provide a number of pump actuating sections which is twice the number of fuel outlet ports whereby fuel is pumped twice to each outlet port during revolution of the rotor.

References Cited in the file of this patent UNITED STATES PATENTS Hodges May 28, Washington Oct. 4, Drouot Jan. 15, Miller Aug. 21, Roosa Apr. 28, Lipinski Nov. 15,

FOREIGN PATENTS France Nov. 25, Australia Nov. 15, France Mar. 26,

each 

